<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://unpkg.com/vue"></script>
    <script>
        window.onload = function () {

            var app3 = new Vue({
                el: '#app',
                methods: {
                    addthing: function () {
                        this.todos.push({name: this.thing, done: false});
                    }
                  ,switchdel:function(idx){
                        this.todos[idx].done=!this.todos[idx].done;

                    }
                    ,show:function(ev){
                    if(ev.keyCode==13){
                        var x={name:this.thing,done:false};
                        this.todos.push(x);
                    }

                    }
                },

                data: {
                    thing: 'null',
                    todos: [
                        {name: '罗军', done: false},
                        {name: '吕领领', done: false},
                        {name: 'll', done: true},


                    ]
                }
                ,computed:{
                    done:function(){
                        var count=0;
                        for(var i=0;i<this.todos.length;i++){
                            if(this.todos[i].done){
                                count++;
                            }
                        }
                        return count;
                    }
                }
            });
        }
    </script>
    <style>.del{text-decoration: line-through}</style>
</head>
<body>
<div id="app">

    <input type="text" v-model="thing" @keydown="show($event)"><br/>

    <button v-on:click="addthing">添加</button>

      <div v-for="(todo,idx) in todos">
          <input type="checkbox" v-bind:checked="todo.done" v-on:click="switchdel(idx)">{{idx}}
          <span v-bind:class="{del: todo.done}">
              {{todo.name}}
          </span>
      </div>
    总共{{todos.length}}事项。{{done}}个已完成，{{todos.length-done}}个未完成
</div>
</body>
</html>